Hi all,
This patch series adds support for the recently ratified Zilsd (Load/Store pair instructions) and Zclsd (Compressed Load/Store pair instructions) extensions to the RISC-V Linux kernel. It covers device tree binding,ISA string parsing, hwprobe exposure, KVM guest handling and selftests.
Zilsd and Zclsd allow more efficient memory access sequences on RV32. My goal is to enable glibc and other user-space libraries to detect these extensions via hwprobe and make use of them for optimized implementations of common routines. To achieve this, the Linux kernel needs to recognize and expose the availability of these extensions through the device tree bindings, ISA string parsing and hwprobe interfaces. KVM support is also required to correctly virtualize these features for guest environments.
The series is structured as follows: - Patch 1: Add device tree bindings documentation for Zilsd and Zclsd - Patch 2: Extend RISC-V ISA extension string parsing to recognize them. - Patch 3: Export Zilsd and Zclsd via riscv_hwprobe - Patch 4: Allow KVM guests to use them. - Patch 5: Add KVM selftests.
This series of patches is a preparatory step toward enabling user-space optimizations in glibc that leverage Zilsd and Zclsd, by providing the necessary kernel-side support.
Please review, and let me know if any adjustments are needed.
Thanks, Pincheng Wang
Pincheng Wang (5): dt-bidings: riscv: add Zilsd and Zclsd extension descriptions riscv: add ISA extension parsing for Zilsd and Zclsd riscv: hwprobe: export Zilsd and Zclsd ISA extensions riscv: KVM: allow Zilsd and Zclsd extensions for Guest/VM KVM: riscv: selftests: add Zilsd and Zclsd extension to get-reg-list test
Documentation/arch/riscv/hwprobe.rst | 8 ++++ .../devicetree/bindings/riscv/extensions.yaml | 39 +++++++++++++++++++ arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/kvm.h | 2 + arch/riscv/kernel/cpufeature.c | 24 ++++++++++++ arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kvm/vcpu_onereg.c | 2 + .../selftests/kvm/riscv/get-reg-list.c | 6 +++ 9 files changed, 87 insertions(+)